CREPE EFFECT BANDAGE

Abstract: There is described a woven bandage which exhibits a crepe effect and which contains elastomeric yarns and composite warp yarns (1) which composite yarns comprise a staple fibre yarn (2) and a textured filament yarn (3) twisted together. The staple fibre yarn (2) forms loops (4) which gives the bandage a crepe effect. There is also described a process for the manufacture of such woven bandages.

Description: CREPE EFFECT BANDAGE The present invention relates to bandages which exhibit a crepe effect and to processes for the manufacture thereof. Crepe bandages are normally used to provide light support and low compression for example in the treatment of sprains and strains and varicose veins. These bandages have sufficient elasticity to enable them to conform to the bandaged area and when secured, to allow limited movement and swelling to take place so that the circulation is not adversely affected. Crepe bandages normally comprise a woven fabric strip or tape containing high twist cotton warp yarns which are usually present in pairs with opposite twist in approximately equal numbers. These high twist warp yarns shrink when the woven fabric is treated for example by boiling in a vat to provide the bandage with elastic stretch and properties and a crepe appearance. However, high twist cotton yarns provide the bandage with a relatively harsh "feel" which can irritate sensitive skin areas. Furthermore, high twist cotton yarns used in conventional crepe bandages usually comprise in excess of 2000 turns per metre of yarn and are thus relatively expensive to manufacture. US Patent No.4236550 describes a bandage which comprises elastic and non-elastic threads. However, the bandages described therein possess relatively high elasticity and are therefore not suitable for use as support dressings in the same manner as a crepe bandage. Indeed US'550 describes the disclosed dressings as being useful as "a fixing band". We have now found a woven bandage which avoids the use of high twist cotton yarns and thereby any problems associated with the use of these yarns and exhibits a crepe effect. According to the present invention we provide a woven bandage which exhibits a crepe effect and which contains elastomeric yarns and composite warp yarns which composite yarns comprise a staple fibre yarn and a textured filament yarn twisted together. Bandages according to the invention may comprise one elastomeric yarn for every 10 to 20 composite yarns. The bandage according to the invention may also comprise warp yarns which are only made of the aforementioned composite and elastomeric yarns. However, in addition, cheaper and more lightweight bandages may be prepared by including textured filament yarns with the elastomeric yarns and composite yarns. Generally, the elastomeric yarns will be elastomeric warp yarns. According to the invention we provide a woven bandage which exhibits a crepe effect and which contains textured filament yarns, elastomeric yarns and composite yarns as hereinbefore described. Such a bandage may have 1 - 3 textured filament yarns for every composite yarn although we prefer such a bandage to comprise one textured filament yarn for every composite yarn. Preferably the textured filament yarns and composite yarns substantially alternate. Generally, such bandages will have one elastomeric yarn for every 10 to 20 yarns which yarns may be alternating composite and textured filament yarns. When the ratio of textured filament yarn to composite yarn is greater than 1:1 the textured filament and elastomeric yarns are preferably in repeating patterns, eg. 1 1 1 1 1 1 l 1 1 1 1 C T T C T T C T C T E I I I I I I l I [ I I where C = a composite yarn in the warp direction T = a textured yarn in the warp direction E = an elastomeric yarn in the warp direction By the term crepe effect we mean that known in the art, that is, eg. having a crinkled or puckered surface. Composite warp yarns used in the woven bandage of the invention are formed of loosely twisted staple fibre and textured filament yarns. Bandages of the invention therefore do not contain any of the high twist yarns used in conventional crepe bandages. The twist level for the composite yarn can suitably be from 60 to 200 turns/metre, preferably less than 140 turns/metre and preferably less than 130 turns/metre. Similarly the twist level for the composite yarn can be suitably at least 80 turns/metre and preferably at least 100 turns/metre. Apt twist levels for the composite yarn are 120-130 turns/metre for example 125 turns/metre. The staple fibre yarns used in the invention are usually characterised by having only limited or no elasticity and good moisture properties. Suitable staple fibre yams for use in composite warp yarns of bandages of the invention include staple cellulosic fibre yarns such as cotton fibre or staple viscose rayon fibre yarns. Such fibre yarns are hydrophilic in nature and therefore can advantageously provide the bandage with absorbent properties. Preferred staple fibre yarns for use in the invention are cotton fibre yarns. Apt yarns of this type are known as 19.68Tex and 36.9Tex (cotton count) cotton yarns. The composite yarns may comprise a cotton yarn and a textured polyamide yarn, preferably the composite yarn comprises a cotton yarn and a textured yarn twisted together. The elastomeric yarn may comprise any natural or synthetic elastomers known er se. Natural elastomers include, for example, natural rubber. Preferred synthetic elastomers include polyurethane elastomers. Preferred polyurethane elastomeric yarns are Spandex polyurethane yarns. Such yarns comprise at least 85% polyurethane. Thus a polyurethane elastomeric yarn need not contain 100% polyurethane. Thus according to the invention we provide a bandage as hereinbefore described wherein the polyurethane elastomeric yarn comprises at least 85% polyurethane, eg. from 85 to 100% polyurethane. Preferred polyurethane elastomeric yarns are those known as LYCRA (Trade Mark). We especially prefer polyurethane elastomeric yarns which have restricted stretching properties. For example, preferred polyurethane elastomeric yarns are those which are wrapped with a less elastomeric filament, ie. a cotton or a nylon wrapping. Such nylon wrapped polyurethane elastomeric yarns are available from Wykes of Leicester in the UK and cotton wrapped polyurethane elastomeric yarns are available from Brierley of Huddersfield in the UK. By the term textured yarn we mean a continuous filament yarn that has been processed to introduce durable crimps, coils, loops or other fine distortions along the lengths of the filaments. The main texturing procedures which are usually applied are conventional procedures known p_er se, and include; (a) the yarn is highly twisted, heat-set and untwisted either as a process of three separate stages or as a continuous process (false-twist texturing). In an infrequently used alternative method, two yarns are continuously folded together, heat-set then separated by unfolding; (b) the yarn is injected into a heated stuffer box either by feed rollers or through a plasticising jet of hot fluid (invariably air or steam). The jet process is sometimes known as jet texturing, hot-air jet texturing, or steam-jet texturing; (c) the yarn is plasticised by passage through a jet of hot fluid and is impacted on to a cooling surface (impact texturing); (d) the heated yarn is passed over a knife-edge (edge crimping); (e) the heated yarn is passed between a pair of gear wheels or through some similar device (gear crimping); (f) the yarn is knitted into a fabric that is heat-set and then unravelled (knit-deknit texturing); (g) the yarn is over-fed through a turbulent air stream (air- texturing, air-jet texturing), so that entangled loops are formed in the filaments; (h) the yarn is composed of bicomponent fibres and is subjected to a hot and/or wet process whereby differential shrinkage occurs. Suitable textured filament yarns for use in composite warp yarns or as textured filament yarns alone in bandages of the invention include textured filament yarns of synthetic fibre polymers such as polyamide or polyester. Preferred textured filament yarns for use in the invention are textured polyamide filament yarns, eg. nylon such as nylon 6,6. Apt yarns of this type are known as 2/78 D Tex nylon. Preferred textured filament warp yarns for use as untwisted yarns are textured polyamide filament yarns such as 2/78 D Tex nylon filament yarns. The textured filament warp yarns used in the invention will normally be in a tensioned state during weaving. Textured filament yarns used in the invention suitably have a crimp rigidity of from 20-50%, at least 30% favourably at least 35% and preferably have a crimp rigidity of at least 40% for example 45%. The crimp rigidity of the textured yarns used in the invention can be determined according to the method given in British Standards Specification No.6663. Bandages according to the invention may contain conventional weft yarns. Suitable weft yarns for use in the bandage according to the invention include any of the staple fibre yarns hereinbefore mentioned in relation to the composite warp yarns, eg. cellulosic fibre yarns such as cotton fibre or staple viscose rayon fibre yarns. Preferred weft yarns are cotton yarns such as 19.68Tex and 36.9Tex cotton yarns. Woven bandages of the invention can conveniently be light- weight or heavy-weight bandages. The bandages according to the invention suitably have a weight per unit area of 40 to 120g/m 2 . Light-weight bandages according to the invention have a weight per unit area of 40 - 60g/m 2 preferably 50 - 60gm 2 . Heavy- weight bandages according to the invention have a weight of 60 - 120g/m 2 , preferably 75 to 90g/m 2 . One favoured embodiment of the invention is a bandage which comprises wrapped polyurethane elastomeric yarns, and 19.68Tex cotton/2/78 D Tex polyamide composite warp yarns which alternate with 2/78 D Tex polyamide warp yarns and 19.68Tex cotton weft yarns, wherein the ratio of the composite yarns plus the polyamide yarns to the polyurethane yarn is 16:1 , eg. a light-weight bandage. A second favoured embodiment of the invention is a bandage which comprises wrapped polyurethane elastomeric yarns, and 19.68Tex cotton/2/78 D Tex polyamide composite warp yarns only and 36.9 Tex cotton weft yarns, wherein the ratio of the composite yarns to the polyurethane elastomeric yarns is 16:1 , eg. a heavy- weight bandage. Bandages of the invention can conveniently be woven on a fabric loom, eg. a narrow fabric loom in widths of 2.5 to 25cm, preferably 5 to 20cm for example in widths of 5, 7.5, 10 or 15cm. The woven bandage can suitable contain 80 to 300 ends per 10cm, eg. 100 to 200 ends per 10cm, preferably 130 to 170 ends per 10cm and more preferably contain 140 to 160 ends per 10cm. Similarly the woven bandage can suitably contain 50 to 110 picks/10cm and preferably contain 60 to 80 picks/10cm. Bandages of the invention stretch in the warp direction to render the bandage conformable to a body portion to which it is to be applied. A bandage of the invention can stretch in the warp direction. The extent to which a bandage may stretch depends, inter alia, on the number of twists of staple fibre yarn around the textured filament yarn and the number of polyurethane elastomeric yarns present. Suitably a bandage of the invention can stretch by at least 50% and preferably by at least 60% of its original length. Apt bandages of the invention have a stretch in the warp direction of 50 to 120% for example 80-100% of its original length. The stretch is measured by subjecting the bandage to a load of 1 kg/cm, according to British Pharmacopoeia Methods of Test for Surgical Dressings - Appendix XXF - Elasticity. According to the invention we also provide an article comprising the bandage material according to the invention. Such articles may include, inter alia, a tubular bandage or an article of clothing. According to a further feature of the invention we provide a method of treatment of one or more of the following disorders; namely, varicose veins, lymphodoema, muscle strain or muscle sprain, which comprises applying a bandage or article according to the invention to the affected site on a patient. We further provide the use of a bandage or article according to the invention in the treatment or alleviation of varicose veins, lymphodoema, muscle strain or muscle sprain. Bandages of the invention exhibit a crepe effect. Such an effect is produced by shrinking the woven bandage fabric. Composite yarns according to the invention are manufactured using an uptwister, preferably an enamel uptwister, using conventional methods known QΘΓ se. Therefore in another aspect the present invention provides a process for making a bandage of the invention which comprises treating a woven bandage fabric containing elastomeric yarns and composite warp yarns which composite yarns comprise a staple fibre yam and a textured filament yarn twisted together to shrink the fabric in the warp direction. During the process the bandage is woven in a tensioned state to produce a woven bandage fabric and is then held in a relaxed condition to allow shrinking to occur. Suitable treatments include passing the fabric in a tensionless state through a steam box followed by a hot air dryer. Alternatively the fabric can be plaited loosely and allowed to relax naturally at room temperature for at least 12 hours. Such processes can advantageously allow the treatment of continuous lengths of bandage fabric. Continuous lengths can then be cut into individual lengths. The spooling tension of the yarn prior to relaxation is usually measured as a function of the diameter of the loaded spool relative to the stretched length of the fabric. Thus the diameter of the spooled bandage is from 40 to 70mm for a length of bandage of from 4 to 4.5m. For example, a heavy-weight bandage of 4.5m in length; preferably has a spooled diameter of from 50 to 70mm, eg. 60mm. A light-weight bandage of 4m in length preferably has a spooled diameter of from 40 to 60mm, eg. 50mm. During the process of relaxation the textured filament warp yams relax or shrink whilst the staple fibre yarns which do not possess elasticity do not shrink. Thus they form loops thereby forming the "crepe effect" on both surfaces of the bandage. The surface loops of staple fibre yarn, for example, cotton yarn, advantageously provide the bandage of the invention with a "soft feel" and an absorbent surface. The textured yarns advantageously provide the bandage of the invention with good elastic stretch properties and the bulky nature of the yarn also provides the bandage with good cover properties. The bandage of the invention does not employ high twist cotton yarns and therefore does not suffer from the harsh feel and high cost problems associated with such high twist yarns. The composite yarns of the present invention will now be illustrated, but in no way limited, by reference to the following drawings: Figure 1 is a schematic view of a composite warp yarn of the invention prior to relaxation, and Figure 2 is a schematic view of a composite warp yarn of Figure 1 after relaxation. Figure 1 illustrates a composite warp yarn (1 ). Composite yarn (1 ) comprises staple fibre yarn (2) such as a cotton yarn and a textured filament yarn (3) such as textured polyamide yarn which are twisted together. The composite yarn (1) is shown in a tensioned state after being woven into a bandage. Figure 2 illustrates the composite yarn (1 ) of Figure 1 after relaxation for example after treatment in a relaxed state in a heated oven. During treatment of yarn (1 ) the textured filament yarn (3) shrinks. The staple fibre yarn (2) has no elastic properties and therefore on relaxation the staple fibre yarn (2) forms loops (4). In use, composite yarns (1 ) may be used as warp yarns in the weaving of crepe effect bandages. Upon relaxation from a stretched state, loops (4) provide the bandage of the invention with a soft feel and a crepe effect. The present invention will now be illustrated by the following examples. Example 1 A light-weight woven bandage of the invention was formed from a woven fabric produced on a narrow fabric loom using a 1 :1 ratio of cotton/nylon composite yarn and nylon warp yarns (145 ends/10cm) and a 16:1 ratio of composite plus nylon yarns and wrapped polyurethane elastomeric yarns; and cotton weft yarns (70 picks/10cm). The cotton and nylon yarns used in this example were 19.68Tex staple fibre cotton yarn and 2/78 D Tex textured nylon filament yarn respectively. The composite warp yarns contain the cotton and nylon yams twisted together (125 turns/metre). The woven fabric in a relaxed state was then subjected to a conventional steam bath to bulk the fabric before being wound into a roll. The bandage was 10cm wide, exhibited crepe effect and had an elastic stretch in the warp direction of 70%. The bandage had a weight per unit area of 53.5g/m 2 . The bandage was found to have a relatively soft feel and also had an aesthetically appealing appearance due to the crepe effect and the cove provided by the bulked fabric and yarns. Example 2 A heavy-weight bandage of the invention was made in the same manner as Example 1 except that the woven fabric contained 152 ends/10cm of warp yarns which were composite cotton/nylon yarns and the weft yarns were 36.9Tex cotton yarns. The bandage of this example had a similar soft feel and appealing appearance as that of Example 1. The bandage had a weight per unit area of 82.5g/m 2 . Bandages of Examples 1 and 2 were applied around the lower part of legs of volunteers. The bandages were found to be highly conformable, comfortable to wear and capable of exerting low compression to protruding areas, ie. the calves of the legs.

Claims: CLAIMS 1. A woven bandage which exhibits a crepe effect and which contains elastomeric yarns and composite warp yams which composite yarns comprise a staple fibre yarn and a textured filament yarn twisted together. 2. A woven bandage which exhibits a crepe effect and which contains elastomeric yarns, textured filament warp yarns and composite warp yarns which composite yarns comprise a staple fibre yarn and a textured filament yam twisted together. 3. A woven bandage according to claims 1 or 2 comprising one elastomeric yarn for every 10 to 20 yarns. 4. A woven bandage according to claims 1 or 2 in which the staple fibre yarn is a staple cellulosic fibre yarn. 5. A woven bandage according to claims 1 or 2 in which the staple fibre yarn is hydrophilic. 6. A woven bandage according to any one of the preceding claims in which the textured filament yarn comprises a synthetic fibre polymer. 7. A woven bandage according to any one of the preceding claims in which the textured filament yarns have a crimp rigidity of from 20 - 50%. 8. A woven bandage according to any one of the preceding claims in which the twist level for the composite yarn is 60 to 200 turns/metre. 9. A woven bandage according to any one of the preceding claims in which the twist level for the composite yam is 125 turns/metre. 10. A woven bandage according to any one of the preceding claims wherein the weft yam is a staple fibre yam. 11. A woven bandage according to any one of the preceding claims wherein the elastomeric yarn comprises a natural or synthetic elastomer. 12. A woven bandage according to any one of the preceding claims having a weight per unit area of 40 to 120g/m 2 . 13. A woven bandage according to any one of the preceding claims containing 100 to 200 ends per 10cm. 14. A woven bandage according to any one of the preceding claims containing 50 to 110 picks/10cm. 15. A woven bandage according to any one of the preceding claims adapted to stretch in the warp direction by at least 50% of its original length. 16. A bandage which comprises 19.68Tex cotton/2/78 D Tex polyamide composite warp yarns which alternate with 2/78 D Tex polyamide warp yarns and 19.68Tex cotton weft yarns. 17. A bandage which comprises 19.68Tex cotton/2/78 D Tex polyamide composite warp yarns only and 36.9Tex cotton weft yarns. 18. A process for making a woven bandage according to claim 1 which comprises treating a woven bandage fabric containing an elastomeric yarn, a textured filament yarn and composite warp yarns which composite yarns comprise a staple fibre yarn and a textured filament yarn to shrink the fabric in the warp direction. 19. A woven bandage according to claim 1 wherein the diameter of the spooled bandage is from 40 to 70mm for a length of bandage of from 4 to 4.5m. 20. A method of treatment of one or more of the following disorders; namely, varicose veins, lymphodoema, muscle strain or muscle sprain, which comprises applying a bandage or article according to claim 1 to the affected site on a patient. 21. An article comprising the bandage material according to claim 1.

Inventors: EVANS JOHN CHRISTOPHER, KININMONTH JULIA, EVANS, JOHN, CHRISTOPHER, KININMONTH, JULIA
Applicants: EVANS JOHN CHRISTOPHER, KININMONTH JULIA, SMITH & NEPHEW, EVANS, JOHN, CHRISTOPHER, KININMONTH, JULIA, SMITH & NEPHEW PLC
Application year: 1994
Main classification: A61F13
IPC codes: A61F13, D03D1, D03D15